1. Field of the Invention
The present invention relates to a wound-type electric storage device including an electrode sheet group that is wound to be accommodated in a casing.
2. Description of Related Art
There are a lithium ion capacitor and a lithium ion secondary battery as an electric storage device used for an electric vehicle or an electric apparatus. As one type of the electric storage device described above, a wound-type electric storage device has been proposed in which a positive electrode sheet and a negative electrode sheet are wound as stacked (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2006-156330). In the electric storage device disclosed in JP-A No. 2006-156330, a metal lithium is adhered onto the negative electrode. Since the metal lithium is incorporated into the electric storage device, lithium ions can be doped from the metal lithium into the negative electrode. Thus, the energy density of the electric storage device can be enhanced.